In response to demands in the market, there have been proposed many technologies which allow a vehicle to urgently travel several hundred kilometers even when a pneumatic tire is punctured while running. Among these many proposals, those disclosed in Japanese Patent Laid-Open Publication No. 10-297226 and Published Japanese Translation of a PCT Application No. 2001-519279 have enabled run-flat traveling by supporting a punctured tire by a support member which is fitted onto a rim in a hollow space of the pneumatic tire assembled to the rim.
The above run-flat support member comprises an annular shell having an support surface formed radially outward in the form of a convexly curved surface and two leg portions located radialy inward, and elastic rings attached to the two leg portions, and is supported on the rim via the elastic rings. The run-flat support member allows existing wheels and rims to be used without any specific modification, and, therefore, can be advantageously adopted without causing confusions in the market.
There are also known tire/wheel assemblies that allow run-flat traveling by supporting the inner surface of a punctured tire by the radially outer support surface of an annular run-flat insert member, formed from a rigid material such as metal or resin in such a shape as a “T” or “I” shape, which is fitted onto a rim in a hollow space of the pneumatic tire assembled to the rim.
However, when a run-fat traveling distance up to the destruction of a tire is examined on tire/wheel assemblies to which the above-mentioned run-flat support member or run-flat insert member is attached using pneumatic tires with different tread patterns, the run-flat traveling distance varies significantly according to the tread patterns. In particular, when pneumatic tires having circumferential grooves extending in a tread surface in a circumferential direction of the tire are used for tire/wheel assemblies, the run-flat traveling distance tends to be shorter, and there is a problem that durability thereof is lowered.